JP3569537B2 - Friction transmission mechanism - Google Patents
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Description
【０００１】
【産業上の利用分野】
本発明は、潤滑剤を介在させて接触させた一対の回転体を有し、一方の回転体を駆動して他方の回転体へ動力を伝動する摩擦伝動機構に関するものである。
【０００２】
【従来の技術】
動力伝動あるいは無段階変速等に供せられる摩擦伝動機構として、駆動側の回転体と従動側の回転体とを潤滑油を介在させて接触させ、油膜内に生じた剪断力を利用して回転体間で動力伝達を行なうものがある。
【０００３】
ところで、この種の摩擦伝動機構では、回転体同士が滑り接触するため、油膜破断による回転体同士の直接接触が生じやすく、潤滑不良に至る可能性が高い。従って、かかる機構においては、油膜破断の発生頻度を如何に少なくするかが極めて重要な問題である。
【０００４】
従来では、回転体の接触面に超仕上げ等の精密な仕上げ加工を施すことにより、回転体表面のあらさの大きさを可能な限り小さくして油膜破断の発生頻度を減少させている。
【０００５】
【発明が解決しようとする課題】
しかし、表面あらさの大きさを小さくするにはコストがかかる。また、高速回転、高負荷等の厳しい使用環境下では、接触部の油膜厚さが薄くなり易く、油膜破断の可能性が高くなる。
【０００６】
そこで、本発明は、回転体同士の接触部における油膜破断の発生頻度を低コストで抑制し、これによって苛酷な使用環境下でも良好な潤滑性を確保することを目的とする。
【０００７】
【課題を解決するための手段】
上記目的の達成のため、本発明では、潤滑剤を介在させて接触させた一対の回転体を有し、高周速度を有する回転体から低周速度を有する回転体へ動力の伝動を行う機構であって、両回転体の接触面に仕上げ加工を施して加工目を形成した摩擦伝動機構において、前記加工目を、何れの回転体においても周方向に沿って設けると共に、高周速側回転体の接触面のあらさを、低周速側回転体の接触面のあらさよりも小さくした。
【０００８】
また、潤滑剤を介在させて接触させた一対の回転体を有し、高周速度を有する回転体から低周速度を有する回転体へ動力の伝動を行う機構であって、両回転体の接触面に仕上げ加工を施して加工目を形成した摩擦伝動機構において、前記加工目を、何れの回転体においても軸方向に沿って設けると共に、高周速側回転体の接触面のあらさを、低周速側回転体の接触面のあらさよりも大きくした。
【０００９】
また、潤滑剤を介在させて接触させた一対の回転体を有し、高周速度を有する回転体から低周速度を有する回転体へ動力の伝動を行う機構であって、両回転体の接触面に仕上げ加工を施して加工目を形成した摩擦伝動機構において、両回転体の加工目の方向性を異ならせると共に、高周速側回転体の加工目を、軸方向に沿って設けた。この場合、高周速側回転体の接触面のあらさを、低周速側回転体の接触面のあらさよりも大きくするのが望ましい。
【００１０】
両回転体の接触面の合成あらさは、０．８μｍ以下であるのが望ましい。
【００１１】
【作用】
▲１▼ 一般に加工目は、互いに平行な筋状の凸部を多数含んでいる。そして、このような加工目を形成すると、潤滑剤は各凸部の間の凹部に帯状に貯留されると考えられる。このため、回転体の表面あらさを小さくすれば、凸部の高さが低くなり、凹部に蓄えられる潤滑剤の量も少なくなる。
【００１２】
一方、回転体の加工目が周方向に形成されていると、回転体の回転時には、潤滑剤が凹部を通って接触部外へ流出し易い。そして、この時の流出量は回転体の回転速度に比例して増大すると考えられる。
【００１３】
従って、加工目を何れの回転体においても周方向に設けた場合に、高周速側回転体の接触面のあらさを、低周速側回転体の接触面のあらさ以下にすれば、接触部から接触部外へ流出する潤滑剤の量が減少し、その結果として接触部の油膜厚さが厚くなるので、油膜破断を防止することが可能となる。
【００１４】
▲２▼ 両回転体は、軸方向に沿って相手部材と直線的に接触する。このため、加工目を軸方向に設けると、潤滑剤を蓄えた帯状の凹部が接触部の全領域を、その側方から波状的に通過することになり、潤滑剤が接触部の全領域にむらなく連続供給される。また、高周速側回転体の凹部は、低周速側回転体に比べてより頻繁に接触部を通過する。
【００１５】
一方、回転体の表面あらさを大きくすると、凸部の高さが高くなり、凹部に蓄えられる潤滑剤の量も増大する。
【００１６】
従って、加工目を、何れの回転体においても軸方向に設けた場合に、高周速側回転体の接触面のあらさを、低周速側回転体の接触面のあらさ以上とすれば、より多くの潤滑剤が接触部の全領域に連続供給され、その結果として油膜破断が防止される。
【００１７】
▲３▼ 後述するように、一般に接触部における潤滑性の良否は、両回転体の接触面におけるあらさの大小関係よりも、加工目の方向性によってより顕著な影響を受ける。従って、少なくとも高周速側の回転体に、潤滑性に優れる軸方向の加工目を設けておけば、油膜破断を防止することができる。
【００１８】
【実施例】
以下、本発明の実施例を図１乃至図８に基づいて説明する。
【００１９】
図１に、無段階変速機に用いられる摩擦伝動機構の構造例を示す。この機構は、球曲面状の外径面を有する駆動側の回転体（２）と、円錐状の外径面を有する従動側の回転体（４）とを具備しており、両回転体（２）（４）は外径面同士を接触させて配置されている。両回転体（２）（４）の回転軸（５）（６）は互いに平行であり且つ同一平面上に位置している。回転体（２）（４）同士を接触させたまま何れか一方の回転体を母線方向に移動させると、回転半径の比が変化するので、無段階変速が可能となる。
【００２０】
この摩擦伝動機構では、駆動側の回転体（２）と従動側の回転体（４）とが潤滑剤（例えば潤滑油）を介在させて接触しており、接触部（７）の油膜内に生じた剪断力を利用して回転体（２）（４）間で動力伝達を行なう。
【００２１】
両回転体（２）（４）の接触部（７）では滑り接触が生じるため、一定量の動力損失は避けられない。このため、接触部（７）における両回転体（２）（４）の周速度は、常に駆動側が大きく従動側が小さい。この関係は、図示の構成とは反対に回転体（４）を駆動側に、回転体（２）を従動側にした場合にも同様に成り立つ。
【００２２】
［実施例１］ 双方の回転体（２）（４）の外径面（接触面）には、超仕上げ等の精密な仕上げ加工を施して、図２に示すように、砥石の加工痕である加工目（８）（９）が周方向に沿って形成される。また、仕上げ加工後の外径面のあらさは、駆動側（高周速側）の回転体（２）の方が、従動側（低周速側）の回転体（４）よりも小さくされている。
【００２３】
一般に加工目（８）（９）は、互いに平行な筋状の凸部を多数含んでいる。そして、このような加工目（８）（９）を形成すると、潤滑油は各凸部の間の凹部に帯状に貯留されると考えられる。このため、回転体の外径面のあらさを小さくすれば、凸部の高さが低くなり、凹部に蓄えられる潤滑油の量も少なくなる。
【００２４】
一方、回転体（２）（４）の加工目（８）（９）が周方向に形成されていると、潤滑油が凹部を通って両回転体（２）（４）の接触部（７）外へ流出し易くなる。そして、この時の流出量は回転体の回転速度に比例して増大すると考えられる。
【００２５】
従って、加工目（８）（９）を何れの回転体（２）（４）においても周方向に設けた場合に、駆動側回転体（２）（高周速側）の表面あらさの大きさを、従動側回転体（４）（低周速側）の表面あらさ以下とすれば、接触部（７）から接触部外へ流出する潤滑油の量が減少し、その結果として接触部（７）の油膜厚さが厚くなるので、油膜破断を防止することが可能となる。
【００２６】
［実施例２］ 図３に本発明の第２の実施例を示す。これは、双方の回転体（２）（４）の加工目（８）（９）を軸方向に向けて設けると共に、駆動側回転体（２）（高周速側）の外径面のあらさを従動側回転体（４）（低周速側）の外径面のあらさよりも大きくしたものである。ここで、軸方向とは、回転軸（５）（６）と平行な方向のみならず、接触部（７）において周方向と直交し得るあらゆる方向を含む意である。
【００２７】
両回転体（２）（４）は、軸方向に沿って直線的に相手部材と接触する。このため、加工目を軸方向に設けると、潤滑油を蓄えた帯状の凹部が接触部（７）の全領域を、その側方から波状的に通過することになり、潤滑油が接触部（７）にむらなく連続供給される。また、駆動側の回転体（２）は高周速を有するため、その凹部は従動側回転体（４）の凹部に比べてより頻繁に接触部（７）を通過する。その一方、回転体の外径面のあらさを大きくすると、凸部の高さが高くなり、凹部に蓄えられる潤滑油の量も増大する。従って、加工目（８）（９）を何れの回転体（２）（４）においても軸方向に設けた場合には、駆動側の回転体（２）のあらさを、従動側の回転体（４）のあらさ以上とすれば、より多くの潤滑油を接触部に供給することができ、その結果として油膜破断を防止することが可能となる。
【００２８】
［実施例３］ 図４に本発明の第３の実施例を示す。これは、従動側の回転体（４）の加工目（９）を周方向に設けると共に、駆動側の回転体（２）の加工目（８）を軸方向に設けたものである。
【００２９】
後述するように、一般に接触部（７）における潤滑性の良否は、両回転体（２）（４）の外径面のあらさの大小関係よりも、当該外径面に設けた加工目（８）（９）の方向性によってより大きな影響を受ける。従って、少なくとも駆動側の回転体（２）に、潤滑性に優れた軸方向の加工目（８）を設けておけば、油膜破断を防止することが可能となる。なお、駆動側回転体（２）の加工目（８）だけでなく、従動側回転体（４）の加工目（９）を軸方向に設けてもこれと同様の作用・効果が得られる。
【００３０】
以下、本発明の効果を実証するために行なった実験について説明する。
【００３１】
［実験１］ この実験は、図５（ａ）に示すように、軸受鋼製の２つの試験円筒Ａ、Ｂを相対回転させてその外径面同士を滑り・転がり接触させ、焼付きが発生する際の回転速度を測定するものである。円筒Ａの回転速度は２００ｒｐｍで一定とし、円筒Ｂの回転速度は２００ｒｐｍから３０秒毎に１００ｒｐｍずつ焼付きが発生するまで増速させている。使用した潤滑油はタービン油で、両円筒の最大接触圧力は１．４ＧＰａである。
【００３２】
円筒Ａ、Ｂの加工目（１１）（１２）は何れも周方向に形成されている。両円筒の中心線平均あらさ（Ｒａ）は、０．０７μｍから０．５５μｍの間の４種類であり、あらさの大きさを適宜組み合わせて実験を行なった。
【００３３】
この実験結果（図５（ｂ）参照）から、周方向の加工目（１１）（１２）同士を接触させた場合には、円筒Ａのあらさの大きさが円筒Ｂのあらさの大きさよりも大きい場合（図中●プロット）の方が、逆の場合（同○プロット）より優れた耐焼付き性を有することが理解できる。即ち、滑り・転がり接触する２物体の加工目が何れも２物体の相対移動方向と平行に設けられている場合は、高周速で回転する物体のあらさを小さくすれば、耐焼付き性を改善できるのである。従って、実施例１で説明したように、双方の加工目（８）（９）を周方向に設けると共に、駆動側回転体（２）（高周速側）の表面あらさを、従動側回転体（４）（低周速側）の表面あらさ以下にすれば、潤滑性能を改善することができる。
【００３４】
なお、ｂ図中の合成あらさとは、円筒Ａの中心線平均あらさ（ＲａＡ）と円筒Ｂの中心線平均あらさ（ＲａＢ）を合成したものをいい、以下の式で定義される。
合成あらさ＝（ＲａＡ２＋ＲａＢ２）０．５
【００３５】
（ｂ）図から明らかなように、焼き付き発生速度は合成あらさと略反比例の関係にある。従って、合成あらさを過度に大きくするのは実用的でない。本出願人の実験によれば、０．８μｍ以下の合成あらさであれば良好な耐焼付き性が得られることが確認できた。
【００３６】
［実験２］ この実験は、実験１と同様の条件下で、円筒Ａと円筒Ｂの加工目（８）（９）を何れも軸方向に向けて焼付き発生速度を測定するものである（図６（ａ）参照）。
【００３７】
この実験結果（同図（ｂ）参照）から、円筒Ｂのあらさを円筒Ａのあらさ以上にすれば（図中○プロット）、逆の場合（同●プロット）よりも耐焼付き性を改善できることが理解できる。即ち、滑り・転がり接触する２物体の加工目が何れも２物体の相対移動方向と直交する方向に設けられている場合は、高周速で回転する物体のあらさを大きくすれば、耐焼付き性を改善できるのである。従って、実施例２で説明したように、双方の加工目（８）（９）を軸方向に設けると共に、駆動側回転体（２）の表面あらさを、従動側回転体（４）の表面あらさ以上にすれば、潤滑性能を改善することができる。
【００３８】
［実験３］ この実験は、実験１と同様の条件下で、円筒Ａ、Ｂの加工目（８）（９）の方向性を異ならせて焼付き発生速度を測定するものである（図７（ａ）参照）。
【００３９】
この実験結果を同図（ｂ）に示す。但し、図中の丸プロット（○、●）は、円筒Ａの加工目（１１）を周方向に形成すると共に、円筒Ｂの加工目（１２）を軸方向に形成した場合を表し、四角プロット（□、■）は円筒Ａの加工目（１１）を軸方向とし、円筒Ｂの加工目（１２）を周方向とした場合を表す。また、白抜きプロット（○、□）は、円筒Ｂのあらさが円筒Ａより大きい場合を表し、黒塗りプロット（●、■）は円筒Ｂのあらさが円筒Ａより小さい場合を表す。
【００４０】
この実験結果から、円筒Ｂの加工目（１２）を軸方向とする場合の方が、円筒Ａの加工目（１１）を軸方向とするよりも耐焼付き性が向上することが理解できる。即ち、滑り・転がり接触する２物体の加工目が軸方向と周方向である場合は、高周速で回転する物体の加工目を軸方向とすれば、耐焼付き性を改善できるのである。従って、実施例３で説明したように、少なくとも駆動側回転体（２）（高周速側）の加工目（８）を軸方向に設ければ、潤滑性能を改善することが可能となる。
【００４１】
また、図７（ｂ）より、耐焼付き性の良否には、円筒Ａ、Ｂのあらさの大小関係よりも、加工目（８）（９）の方向性の方がより大きな影響を与えることが理解できる。従って、加工目（８）（９）の方向性を回転体（２）（４）の間で異ならせる場合には、回転体（２）（４）の周速度と加工目（８）（９）の方向性を十分に考慮する必要がある。
【００４２】
なお、以上の説明では、回転体（２）（４）の外径面が球曲面と円錐状面である摩擦伝動機構を例に挙げたが、本発明の適用範囲はこれに限定されるものではなく、回転体（２）（４）の一方、若しくは、その双方が円柱状である場合にも同様に適用可能である。また、図１〜図４では、図８（ａ）に示すように回転体（２）（４）同士を外接させて動力伝動を行なう場合を例示したが、本発明は、同図（ｂ）に示すように、円柱状の回転体（１４）を円筒状の回転体（１５）に内接させて動力伝達を行なう場合にも同様に適用することができる。
【００４３】
【発明の効果】
このように本発明によれば、加工目を、何れの回転体においても周方向に設けると共に、高周速側回転体の接触面のあらさを、低周速側回転体の接触面のあらさ以下としているので、回転体の回転時に接触部から接触部外へ流出する潤滑剤の量が少なくなる。従って、苛酷な使用環境下でも油膜破断による潤滑不良を防止することができる。また、少なくとも一方の回転体の仕上げあらさはラフでよいので、従来品に比べて加工コストを抑制することができる。
【００４４】
また、加工目を、何れの回転体においても軸方向に沿って設けると共に、高周速側回転体の接触面のあらさを、低周速側回転体の接触面のあらさより以上とすれば、より多くの潤滑剤が接触部の全領域に連続供給される。このため、上述の場合と同様に、苛酷な使用環境下でも低コストで潤滑不良を防止することができる。
【００４５】
少なくとも高周速側回転体に、潤滑性に優れる軸方向の加工目を設けておけば、油膜破断による潤滑不良の防止に一定の効果を奏することができる。そして、このように加工目の方向性が適当であれば、仕上げ加工の精度が多少ラフであっても潤滑性の良否はそれほど大きな影響を受けない。従って、加工コストを抑制することができる。
【００４６】
一般に、接触部における潤滑性能は、一対の回転体の接触面における合成あらさと略反比例の関係にあるため、合成あらさを過度に大きくするのは実用的でない。本出願人の実験によれば、０．８μｍ以下の合成あらさであれば満足すべき結果が得られることが明らかになった。
【図面の簡単な説明】
【図１】摩擦伝動機構の一例を示す側面図である。
【図２】両回転体に周方向の加工目を設けた摩擦伝動機構の側面図である。
【図３】両回転体に軸方向の加工目を設けた摩擦伝動機構の側面図である。
【図４】駆動側の回転体に軸方向の加工目を設けると共に、従動側の回転体に周方向の加工目を設けた摩擦伝動機構の側面図である。
【図５】実験装置を示す斜視図（ａ）、及び、実験結果を表すグラフである（ｂ）。
【図６】実験装置を示す斜視図（ａ）、及び、実験結果を表すグラフである（ｂ）。
【図７】実験装置を示す斜視図（ａ）、及び、実験結果を表すグラフである（ｂ）。
【図８】図１中のＡ方向からみた外接型摩擦伝動機構の正面図（ａ）、及び、内接型摩擦伝動機構の正面図である。
【符号の説明】
２ 回転体（高周速度側）
４ 回転体（低周速度側）
７ 接触部
８ 加工目
９ 加工目[0001]
[Industrial applications]
The present invention relates to a friction transmission mechanism that includes a pair of rotating bodies that are brought into contact with a lubricant interposed therebetween, and drives one of the rotating bodies to transmit power to the other rotating body.
[0002]
[Prior art]
As a friction transmission mechanism used for power transmission or stepless transmission, the rotating body on the driving side and the rotating body on the driven side are brought into contact with lubricating oil, and rotated using the shear force generated in the oil film. Some perform power transmission between the bodies.
[0003]
By the way, in this type of friction transmission mechanism, since the rotating bodies are in sliding contact with each other, direct contact between the rotating bodies due to oil film breakage is likely to occur, and there is a high possibility of poor lubrication. Therefore, in such a mechanism, it is an extremely important problem how to reduce the frequency of occurrence of oil film breakage.
[0004]
Conventionally, a precision finishing process such as superfinishing is performed on a contact surface of a rotating body to reduce the roughness of the rotating body surface as much as possible to reduce the frequency of oil film breakage.
[0005]
[Problems to be solved by the invention]
However, it is costly to reduce the surface roughness. Further, in a severe use environment such as high-speed rotation and high load, the oil film thickness of the contact portion tends to be thin, and the possibility of oil film breakage increases.
[0006]
Therefore, an object of the present invention is to suppress the occurrence frequency of oil film rupture at a contact portion between rotating bodies at a low cost, thereby ensuring good lubrication even in a severe use environment.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a mechanism for transmitting power from a rotating body having a high peripheral speed to a rotating body having a low peripheral speed, comprising a pair of rotating bodies contacted with a lubricant interposed therebetween. In the friction transmission mechanism in which the contact surface of both the rotating bodies is subjected to finish processing to form a processing line, the processing line is provided along the circumferential direction in any of the rotating bodies, and the rotation at the high peripheral speed is performed. The roughness of the contact surface of the body is made smaller than the roughness of the contact surface of the low peripheral speed side rotating body.
[0008]
A mechanism for transmitting power from a rotating body having a high peripheral velocity to a rotating body having a low peripheral velocity, comprising a pair of rotating bodies contacted with a lubricant interposed therebetween. In the friction transmission mechanism in which the surface is subjected to finish machining to form a machining stitch, the machining stitch is provided along the axial direction in any rotating body, and the roughness of the contact surface of the high peripheral speed side rotating body is reduced. The roughness was larger than the roughness of the contact surface of the peripheral rotating body.
[0009]
A mechanism for transmitting power from a rotating body having a high peripheral velocity to a rotating body having a low peripheral velocity, comprising a pair of rotating bodies contacted with a lubricant interposed therebetween. In the friction transmission mechanism in which the surface is subjected to finish processing to form a processing line, the direction of the processing line of both rotating bodies is made different, and the processing line of the high peripheral speed side rotating body is provided along the axial direction. In this case, it is desirable that the roughness of the contact surface of the high peripheral speed rotating body be larger than the roughness of the contact surface of the low peripheral speed rotating body.
[0010]
It is desirable that the combined roughness of the contact surfaces of the two rotating bodies be 0.8 μm or less.
[0011]
[Action]
{Circle around (1)} In general, a processed line includes a large number of parallel line-shaped convex portions. Then, when such processed lines are formed, it is considered that the lubricant is stored in a band shape in the concave portions between the convex portions. For this reason, if the surface roughness of the rotating body is reduced, the height of the convex portion decreases, and the amount of the lubricant stored in the concave portion also decreases.
[0012]
On the other hand, if the processing line of the rotating body is formed in the circumferential direction, the lubricant easily flows out of the contact portion through the recess when the rotating body is rotated. It is considered that the outflow amount at this time increases in proportion to the rotation speed of the rotating body.
[0013]
Therefore, in the case where the machining stitch is provided in any of the rotating bodies in the circumferential direction, if the roughness of the contact surface of the high peripheral speed rotating body is less than or equal to the roughness of the contact surface of the low peripheral speed rotating body, the contact portion The amount of the lubricant flowing out of the contact portion from the contact portion decreases, and as a result, the oil film thickness of the contact portion increases, so that it is possible to prevent the oil film from breaking.
[0014]
{Circle around (2)} Both rotating bodies come into linear contact with the mating member along the axial direction. For this reason, when the processing line is provided in the axial direction, the band-shaped concave portion storing the lubricant passes through the entire region of the contact portion in a wavy manner from the side thereof, and the lubricant spreads over the entire region of the contact portion. It is supplied evenly and continuously. Further, the concave portion of the high peripheral speed rotating body passes through the contact portion more frequently than the low peripheral speed rotating body.
[0015]
On the other hand, when the surface roughness of the rotating body is increased, the height of the convex portion is increased, and the amount of the lubricant stored in the concave portion is also increased.
[0016]
Therefore, when the machining line is provided in any of the rotating bodies in the axial direction, the roughness of the contact surface of the high peripheral speed rotating body is set to be equal to or greater than the roughness of the contact surface of the low peripheral speed rotating body. A large amount of lubricant is continuously supplied to the entire area of the contact portion, so that oil film rupture is prevented.
[0017]
{Circle around (3)} As will be described later, the quality of lubrication at the contact portion is generally more significantly affected by the directionality of the machining pattern than by the magnitude relationship of the roughness at the contact surfaces of the two rotating bodies. Therefore, if at least the rotating body on the high peripheral speed side is provided with an axially processed line having excellent lubricating properties, oil film breakage can be prevented.
[0018]
【Example】
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0019]
FIG. 1 shows a structural example of a friction transmission mechanism used in a continuously variable transmission. This mechanism includes a driving-side rotator (2) having a spherical outer surface and a driven-side rotator (4) having a conical outer surface. 2) and (4) are arranged with their outer diameter surfaces in contact with each other. The rotation axes (5) and (6) of both rotating bodies (2) and (4) are parallel to each other and are located on the same plane. If one of the rotating bodies is moved in the generatrix direction while keeping the rotating bodies (2) and (4) in contact with each other, the ratio of the radius of gyration changes, so that a stepless speed change is possible.
[0020]
In this friction transmission mechanism, the rotating body (2) on the driving side and the rotating body (4) on the driven side are in contact with each other with a lubricant (eg, lubricating oil) interposed therebetween. Power transmission is performed between the rotating bodies (2) and (4) using the generated shearing force.
[0021]
Since a sliding contact occurs at the contact portion (7) of the two rotating bodies (2) and (4), a certain amount of power loss is inevitable. For this reason, the peripheral speed of both rotating bodies (2) and (4) at the contact portion (7) is always large on the driving side and small on the driven side. This relationship similarly holds when the rotating body (4) is on the driving side and the rotating body (2) is on the driven side, contrary to the illustrated configuration.
[0022]
[Example 1] The outer diameter surfaces (contact surfaces) of both rotating bodies (2) and (4) are subjected to precise finishing such as super finishing, and as shown in FIG. Certain features (8) and (9) are formed along the circumferential direction. In addition, the roughness of the outer diameter surface after finishing is smaller on the rotating body (2) on the driving side (high peripheral speed side) than on the driven side (low peripheral speed side). I have.
[0023]
Generally, the processing eyes (8) and (9) include a large number of parallel streaks. When such processing lines (8) and (9) are formed, it is considered that the lubricating oil is stored in a band shape in the concave portions between the convex portions. For this reason, if the roughness of the outer diameter surface of the rotating body is reduced, the height of the convex portion decreases, and the amount of lubricating oil stored in the concave portion also decreases.
[0024]
On the other hand, when the processing eyes (8) and (9) of the rotating bodies (2) and (4) are formed in the circumferential direction, the lubricating oil passes through the concave portions and the contact portions (7) of the two rotating bodies (2) and (4). ) It is easy to flow out. It is considered that the outflow amount at this time increases in proportion to the rotation speed of the rotating body.
[0025]
Therefore, when the machining eyes (8) and (9) are provided in any of the rotating bodies (2) and (4) in the circumferential direction, the surface roughness of the driving-side rotating body (2) (high peripheral speed side) is large. Is less than or equal to the surface roughness of the driven side rotating body (4) (low peripheral speed side), the amount of lubricating oil flowing out of the contact portion from the contact portion (7) is reduced, and as a result, the contact portion (7 Since the thickness of the oil film becomes larger, it is possible to prevent the oil film from breaking.
[0026]
[0027]
The two rotating bodies (2) and (4) linearly contact the counterpart member along the axial direction. For this reason, when the processing line is provided in the axial direction, the band-shaped concave portion storing the lubricating oil passes through the entire region of the contact portion (7) in a wavy manner from the side thereof, and the lubricating oil passes through the contact portion (7). 7) It is continuously supplied evenly. Further, since the rotating body (2) on the driving side has a high peripheral speed, the concave portion passes through the contact portion (7) more frequently than the concave portion of the driven rotating body (4). On the other hand, when the roughness of the outer diameter surface of the rotating body is increased, the height of the convex portion is increased, and the amount of lubricating oil stored in the concave portion is also increased. Therefore, when the processing eyes (8) and (9) are provided in any of the rotating bodies (2) and (4) in the axial direction, the roughness of the driving-side rotating body (2) is changed to the driven-side rotating body ( If the roughness is not less than 4), more lubricating oil can be supplied to the contact portion, and as a result, oil film breakage can be prevented.
[0028]
Third Embodiment FIG. 4 shows a third embodiment of the present invention. This is one in which a processing portion (9) of the driven-side rotating body (4) is provided in the circumferential direction, and a processing portion (8) of the driving-side rotating body (2) is provided in the axial direction.
[0029]
As described later, in general, the quality of the lubrication property of the contact portion (7) depends on the degree of roughness of the outer diameter surfaces of the two rotating bodies (2) and (4), rather than the degree of roughness of the outer diameter surfaces. ) It is more greatly affected by the direction of (9). Therefore, if at least the axially processed portion (8) having excellent lubricity is provided on the rotating body (2) on the driving side, it is possible to prevent oil film rupture. The same operation and effect can be obtained by providing not only the machining step (8) of the drive-side rotating body (2) but also the machining step (9) of the driven-side rotating body (4) in the axial direction.
[0030]
Hereinafter, experiments performed to demonstrate the effects of the present invention will be described.
[0031]
[Experiment 1] In this experiment, as shown in FIG. 5 (a), two test cylinders A and B made of bearing steel are rotated relative to each other to bring their outer diameter surfaces into sliding and rolling contact, and seizure occurs. This is to measure the rotation speed when performing. The rotation speed of the cylinder A is constant at 200 rpm, and the rotation speed of the cylinder B is increased from 200 rpm by 100 rpm every 30 seconds until seizure occurs. The lubricating oil used was turbine oil, and the maximum contact pressure between both cylinders was 1.4 GPa.
[0032]
The processing lines (11) and (12) of the cylinders A and B are all formed in the circumferential direction. The center line average roughness (Ra) of both cylinders is four types between 0.07 μm and 0.55 μm, and the experiment was performed by appropriately combining the roughness sizes.
[0033]
From the experimental results (see FIG. 5 (b)), when the circumferentially processed lines (11) and (12) are brought into contact with each other, the roughness of the cylinder A is larger than the roughness of the cylinder B. It can be understood that the case (● plot in the figure) has better seizure resistance than the reverse case (○ plot). In other words, if the machining edges of two objects that come into sliding / rolling contact are both provided in parallel with the relative movement direction of the two objects, reducing the roughness of the object rotating at a high peripheral speed improves the seizure resistance. You can. Therefore, as described in the first embodiment, both the processing lines (8) and (9) are provided in the circumferential direction, and the surface roughness of the driving-side rotating body (2) (high peripheral speed side) is reduced by the driven-side rotating body. (4) Lubrication performance can be improved by reducing the surface roughness to (lower peripheral speed side) or less.
[0034]
Note that the combined roughness in the figure b is a combination of the center line average roughness (RaA) of the cylinder A and the center line average roughness (RaB) of the cylinder B, and is defined by the following equation.
Synthetic roughness = (RaA 2 + RaB 2 ) 0.5
[0035]
(B) As is apparent from the figure, the burn-in occurrence speed is substantially inversely proportional to the combined roughness. Therefore, it is not practical to make the composite roughness excessively large. According to experiments by the present applicant, it was confirmed that good seizure resistance can be obtained with a synthetic roughness of 0.8 μm or less.
[0036]
[Experiment 2] In this experiment, under the same conditions as in Experiment 1, all of the machining points (8) and (9) of the cylinder A and the cylinder B were directed in the axial direction to measure the seizure generation speed ( FIG. 6 (a)).
[0037]
From the experimental results (see FIG. 3 (b)), it can be seen that the seizure resistance can be improved when the roughness of the cylinder B is equal to or greater than the roughness of the cylinder A (○ plot in the figure) as compared to the opposite case (（plot in the figure). It can be understood. In other words, when the machining edges of two objects that are in sliding and rolling contact are both provided in a direction perpendicular to the direction of relative movement of the two objects, if the roughness of the object rotating at a high peripheral speed is increased, the seizure resistance is improved. Can be improved. Therefore, as described in the second embodiment, both the processing lines (8) and (9) are provided in the axial direction, and the surface roughness of the driving-side rotating body (2) is changed to the surface roughness of the driven-side rotating body (4). By doing so, the lubrication performance can be improved.
[0038]
[Experiment 3] In this experiment, under the same conditions as in Experiment 1, the seizure generation speed was measured by changing the directionality of the processed portions (8) and (9) of the cylinders A and B (FIG. 7). (A)).
[0039]
The result of this experiment is shown in FIG. Here, the circle plots (○, ●) in the figure represent the case where the processing line (11) of the cylinder A is formed in the circumferential direction and the processing line (12) of the cylinder B is formed in the axial direction. (□, ■) represent the case where the machined portion (11) of the cylinder A is set in the axial direction and the machined portion (12) of the cylinder B is set in the circumferential direction. Open plots (○, □) represent the case where the roughness of the cylinder B is larger than the cylinder A, and black plots (●, Δ) represent the case where the roughness of the cylinder B is smaller than the cylinder A.
[0040]
From this experimental result, it can be understood that the seizure resistance is improved when the machined part (12) of the cylinder B is set in the axial direction as compared with the case where the machined part (11) of the cylinder A is set in the axial direction. In other words, when the machining of two objects that come into sliding and rolling contact is in the axial direction and the circumferential direction, the seizure resistance can be improved if the machining of the object rotating at a high peripheral speed is in the axial direction. Therefore, as described in the third embodiment, if at least the machining portion (8) of the driving-side rotating body (2) (high peripheral speed side) is provided in the axial direction, the lubrication performance can be improved.
[0041]
Further, from FIG. 7B, the directionality of the processed portions (8) and (9) has a greater effect on the quality of the seizure resistance than the relationship between the roughness of the cylinders A and B. It can be understood. Therefore, in the case where the directionality of the machining points (8) and (9) is different between the rotating bodies (2) and (4), the peripheral speeds of the rotating bodies (2) and (4) and the machining points (8) and (9) are different. ) Needs to be fully considered.
[0042]
In the above description, the friction transmission mechanism in which the outer diameter surfaces of the rotating bodies (2) and (4) are a spherical surface and a conical surface has been described as an example, but the scope of the present invention is limited to this. However, the present invention can be similarly applied to a case where one or both of the rotating bodies (2) and (4) are cylindrical. Also, FIGS. 1 to 4 illustrate the case where the power transmission is performed by circumscribing the rotating bodies (2) and (4) as shown in FIG. As shown in (1), the present invention can be similarly applied to the case where power transmission is performed by bringing a cylindrical rotating body (14) into inscribed contact with a cylindrical rotating body (15).
[0043]
【The invention's effect】
As described above, according to the present invention, the processing line is provided in any of the rotating bodies in the circumferential direction, and the roughness of the contact surface of the high peripheral speed rotating body is equal to or less than the roughness of the contact surface of the low peripheral speed rotating body. Therefore, the amount of the lubricant that flows out of the contact portion from the contact portion when the rotating body rotates is reduced. Therefore, poor lubrication due to oil film rupture can be prevented even in a severe use environment. Further, since the finish roughness of at least one of the rotating bodies may be rough, the processing cost can be suppressed as compared with the conventional product.
[0044]
Further, if the processing line is provided along the axial direction in any rotating body, and the roughness of the contact surface of the high peripheral speed rotating body is more than the roughness of the contact surface of the low peripheral speed rotating body, More lubricant is continuously supplied to the entire area of the contact portion. Therefore, as in the case described above, it is possible to prevent poor lubrication at low cost even in a severe use environment.
[0045]
If at least the high circumferential speed side rotating body is provided with an axially processed line excellent in lubricity, a certain effect can be exerted in preventing poor lubrication due to oil film breakage. If the processing direction is appropriate, the quality of the lubrication is not significantly affected even if the accuracy of the finishing processing is somewhat rough. Therefore, the processing cost can be suppressed.
[0046]
Generally, since the lubricating performance at the contact portion is substantially inversely proportional to the combined roughness on the contact surfaces of the pair of rotating bodies, it is not practical to make the combined roughness excessively large. According to experiments by the present applicant, it has been found that satisfactory results can be obtained with a synthetic roughness of 0.8 μm or less.
[Brief description of the drawings]
FIG. 1 is a side view showing an example of a friction transmission mechanism.
FIG. 2 is a side view of a friction transmission mechanism in which both rotating bodies are provided with circumferential processing stitches.
FIG. 3 is a side view of a friction transmission mechanism in which both rotating bodies are provided with processing lines in the axial direction.
FIG. 4 is a side view of a friction transmission mechanism in which an axially processed portion is provided on a driving-side rotating body, and a circumferentially-directional processed portion is provided on a driven-side rotating body.
5A is a perspective view showing an experimental apparatus, and FIG. 5B is a graph showing experimental results.
6A is a perspective view showing an experimental apparatus, and FIG. 6B is a graph showing experimental results.
7A is a perspective view showing an experimental apparatus, and FIG. 7B is a graph showing experimental results.
FIG. 8A is a front view of the circumscribed friction transmission mechanism viewed from the direction A in FIG. 1, and FIG.
[Explanation of symbols]
2 rotating body (high peripheral speed side)
4 rotating body (low peripheral speed side)
7 Contact
Claims (5)
前記加工目を、何れの回転体においても周方向に沿って設けると共に、高周速側回転体の接触面のあらさを、低周速側回転体の接触面のあらさよりも小さくしたことを特徴とする摩擦伝動機構。A mechanism for transmitting power from a rotating body having a high peripheral velocity to a rotating body having a low peripheral velocity, having a pair of rotating bodies contacted with a lubricant interposed therebetween. In a friction transmission mechanism that has been subjected to finish processing to form a processing line,
The machining stitch is provided along the circumferential direction in any rotating body, and the roughness of the contact surface of the high peripheral speed rotating body is made smaller than the roughness of the contact surface of the low peripheral speed rotating body. And friction transmission mechanism.
前記加工目を、何れの回転体においても軸方向に沿って設けると共に、高周速側回転体の接触面のあらさを、低周速側回転体の接触面のあらさよりも大きくしたことを特徴とする摩擦伝動機構。A mechanism for transmitting power from a rotating body having a high peripheral velocity to a rotating body having a low peripheral velocity, having a pair of rotating bodies contacted with a lubricant interposed therebetween. In a friction transmission mechanism that has been subjected to finish processing to form a processing line,
The machining stitch is provided along the axial direction in any rotating body, and the roughness of the contact surface of the high peripheral speed rotating body is larger than the roughness of the contact surface of the low peripheral speed rotating body. And friction transmission mechanism.
両回転体の加工目の方向性を異ならせると共に、高周速側回転体の加工目を、軸方向に沿って設けたことを特徴とする摩擦伝動機構。A mechanism for transmitting power from a rotating body having a high peripheral velocity to a rotating body having a low peripheral velocity, having a pair of rotating bodies contacted with a lubricant interposed therebetween. In a friction transmission mechanism that has been subjected to finish processing to form a processing line,
A friction transmission mechanism characterized in that the direction of machining of the two rotating bodies is different, and the machining of the high peripheral speed side rotating body is provided along the axial direction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24461293A JP3569537B2 (en) | 1993-09-30 | 1993-09-30 | Friction transmission mechanism |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24461293A JP3569537B2 (en) | 1993-09-30 | 1993-09-30 | Friction transmission mechanism |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07103303A JPH07103303A (en) | 1995-04-18 |
| JP3569537B2 true JP3569537B2 (en) | 2004-09-22 |
Family
ID=17121330
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24461293A Expired - Fee Related JP3569537B2 (en) | 1993-09-30 | 1993-09-30 | Friction transmission mechanism |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3569537B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106996436A (en) * | 2016-01-26 | 2017-08-01 | 丰田自动车株式会社 | Gear mechanism |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004031615A2 (en) * | 2002-09-30 | 2004-04-15 | Ulrich Rohs | Epicyclic gear |
| JP2006077852A (en) * | 2004-09-08 | 2006-03-23 | Jtekt Corp | Rolling/sliding component |
| JP4930242B2 (en) * | 2007-07-20 | 2012-05-16 | 村田機械株式会社 | Machine tool with loader |
-
1993
- 1993-09-30 JP JP24461293A patent/JP3569537B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106996436A (en) * | 2016-01-26 | 2017-08-01 | 丰田自动车株式会社 | Gear mechanism |
| US10495190B2 (en) | 2016-01-26 | 2019-12-03 | Toyota Jidosha Kabushiki Kaisha | Gear assembly |
| CN106996436B (en) * | 2016-01-26 | 2019-12-13 | 丰田自动车株式会社 | Gear mechanism |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07103303A (en) | 1995-04-18 |
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